1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a control of a circuit, and more particularly, to a circuit and a method capable of generating an analog signal.
2. Description of the Related Art
Recently, various kinds of electronic devices are being used. An electronic circuit included in an electronic device is controlled by an electric signal and performs its own function. A variety of circuit control methods are utilized to obtain a result of performing the function of the electronic circuit.
For instance, an image sensor is used to generate image information. Pixels of the image sensor receive light and generate a current having an intensity that varies according to the intensity of the received light. Further, digital signals corresponding to the pixels are generated. Digital values of the generated digital signals vary according to the intensity of generated current. Based on the generated digital signals, image information is generated. Herein, circuit control for converting an analog signal (i.e., current) into a digital signal is performed when the image sensor generates the image information.
In the above example, the intensity of the generated current needs to be determined to decide a digital value corresponding to a digital signal. A reference signal to be compared with the generated current is required to determine the intensity of the generated current. The reference signal is called as a ramp signal. The ramp signal has a value that stepwise increases or decreases within a predetermined interval. An interval which a value corresponding to the intensity of the generated current belongs to is determined by comparing the intensity of the generated current with the intensity of the ramp signal. A digital value corresponding to the generated digital signal is decided based on the interval which the value corresponding to the intensity of the generated current belongs to.
The ramp signal is a reference signal that is to be compared with an analog signal (e.g., a current). The ramp signal is an analog signal, too. That is, when the image sensor generates image information, circuit control is performed to generate the ramp signal which is an analog signal.